The reason why oral cancer is so prevalent in the US is because
they are sexually active at an early stage, plus they have multiple
sex partners and without protection. All these are risk factors for
getting oropharyngeal carcinoma. Agent is called human papilloma
virus (HPV) which has various subtypes, some of which causes penile
warts, cervical cancer, etc...
That aside, imagine if u gag and puke ur last meal out onto his
member.... 
